Windows 7: Routing issues on multi-homed laptop

Hi,
On my home network I have an ESX server runnign some VMs sitting behind a vyatta router. Ideally I'd like to be able to access the ESX server and it's VM from the public side of the vyatta router but I can't yet - another issue. So to work with the VM I have to plugin a wired interface connected to the VM network.

This itself behaves very oddly. That is, even thogh the wired network is pysically connected to my laptop the hosts on the network are not pingable unless I configure a default gateway for that network. How can this be when the network is directly connected? It's almost like the traffic is defaulting to the wireless (internet facing) interface rather than going to the legitimately addressed interface.

I have read comments here and there from people saying windows networking in multi-homed scenarios is broken although I've not seeing anything exactly spelling out what the problems and/or fixes are. But I am wondering if the behaviour I'm seeing here is sympomatic of that.

If someone can help to understand what's going on I'll appreciate it.